ANKARA, April 8 (Xinhua) -- U.S. Secretary of State John Kerry's visit to Turkey on Sunday was meant to lay the groundwork for the Turkish prime minister's visit to Washington next month, analysts said.

"There are a lot of regional issues that the United States wants to work with Turkey," Mehmet Seyfettin Erol, a professor of international relations at Ankara-based Gazi University, told Xinhua.

"Kerry's visit was hoped to smooth out differences between Washington and Ankara on the eve of high-profile meeting between (Turkish Prime Minister Recep Tayyip) Erdogan and (U.S. President Barack) Obama," he added.

During Kerry's stay in Turkey, Syria, Iran, Iraq and Israel "were the focus of" his talks with the Turkish side, he noted.

Erdogan's long-awaited visit to Washington is slated for May 16.

The United States is very much concerned about the fragile relationship Obama brokered between Turkey and Israel during a trip to Israel last month.

At the Sunday meeting with Turkish Foreign Minister Ahmet Davutoglu, Kerry again urged Turkey and Israel to appoint ambassadors to each other and restore full relationship.

Under U.S. pressure, Israeli Prime Minister Benjamin Netanyahu finally caved in last month to Turkish demand for an official apology for the killing of nine Turkish citizens by Israeli commandos who raided a humanitarian aid ship en route to Gaza in May 2010.

The two are set to discuss compensations to families of victims while preparing steps to upgrade their diplomatic ties to ambassadorial level.

"The question as to how the relationship (between Turkey and Israel) will proceed from now on demonstrates the importance of diplomacy in the short term," said Emrah Usta, an Istanbul-based political analyst.

"Bilateral relations between Turkey and Israel will improve if Israel lifts its blockade on Gaza or allows the passage of humanitarian cargo to the area," he said.

Syria was also on Kerry's agenda as the United States is scrambling to contain the spillover of the Syrian crisis to neighboring countries, especially Jordan, Lebanon and Turkey.

Mehmet Ozcan, chairman of the Ankara Strategy Institute, believes that Kerry's visit to Turkey means that the circle around Syria has been shrinking down.

The United States also wants to see Turkey engaged in long-stalled Israeli-Palestinian peace talks and give them a fresh push even though Washington has consistently downplayed expectations for anything substantial on that front.

From Istanbul, Kerry will head to Israel and Palestinian territories for meetings with both Israeli and Palestinian officials.

Turkey, having strong relations with both Hamas and Fatah, can contribute to the Middle East peace process, Turkish analysts said.

Kerim Balci, a Middle East analyst and chief editor of Turkish Review, believes that Turkey should do whatever it can to help move the stalled talks between Israel and the Palestinians. He suggested that Erdogan seize the opportunity presented to him during his upcoming visit to Gaza and Ramallah.

"Our prime minister's visit to Gaza should be seen as an opportunity for triggering rapprochement between Hamas and Fatah and convincing Hamas to recognize the state of Israel and put an end to terror and take the lead in the negotiations between Israel and Palestine. This would be the greatest favor we can do to Palestinians in general and Hamas in particular," he said.

The political governance crisis in Iraq and the West's standoff with Iran over the latter's controversial nuclear program were also discussed by Kerry and Turkish officials on Sunday. Those issues will also be talked over during the meeting of Erdogan and Obama next month.